EP1943369B1 - Method for coating a component - Google Patents

Description

The invention relates to the production of functional surfaces on fiber-reinforced composite materials using thermal and kinetic spraying, wherein the protection of the component surface against wear, mechanical damage, deposits and adhesions, and the improvement in terms of sheet delivery (release behavior) is given a special significance.

Fiber reinforced composites, particularly those having a polymer matrix and carbon fiber reinforced polymers, can be used to manufacture components having exceptional mechanical and physical properties, e.g. have a low density, a high tensile and torsional strength, and a high elastic modulus or a high stiffness. A variety of high strength fiber materials can be used, including carbon fibers, glass fibers, silicon carbide fibers, and many other oxides, carbides, and other materials. Likewise, a wide variety of polymeric materials, including thermosetting resins, e.g. Phenolic resins, epoxy resins and many other materials. The fibers can be very long and arranged in specific patterns, or they can be relatively short and random. When arranged in specific patterns, long fibers may be oriented in a single direction or arranged in patterns designed to give the fiber reinforced composite a two- or three-dimensional strength. Thus, the mechanical properties of the structure of the fiber reinforced composite material can be tailored to the specific requirements of a component.

Unfortunately, the surfaces of fiber reinforced composites have low wear resistance, especially to adhesive, abrasive, and erosive wear, and their adhesion and wetting properties are inadequate for many applications, such as in the paper industry. In addition, they are often susceptible to oxidation or other forms of corrosion, require heat protection, lack the necessary optical and electrical characteristics, and the like. As a result, the insert is fiber reinforced Composite materials in many applications limits or requires the use of metallic or ceramic inserts or coatings in those areas that are exposed to contact with other components or fabrics and thus to increased wear.

Nevertheless, the use of fiber reinforced composite rolls in the printing, paper and film industries is particularly interesting because they are much lighter and stiffer, and therefore easier and safer to handle than, for example, steel rolls, and thus less energy due to their lower inertia and time for their acceleration and deceleration, allowing for cost savings not only in handling and assembly but also in operation. In order to provide the working surfaces of the rolls with the required properties, the rolls in this case have a metallic, ceramic or carbide coating or mixtures thereof with plastics, which provides the required wear resistance and other necessary properties. Using thermal spray techniques, a wide variety of metallic and ceramic layers, cermet layers, i. Carbide particles embedded in a metallic matrix, and some polymer coatings are produced.

The thermal spray family includes detonation spraying (including Super D-Gun ^™ ), high-velocity flame spraying and its variants such as air-fuel injection, plasma spraying, flame spraying and electric wire arc spraying. In most thermal coating processes, the sprayed material in the form of powder, wire, or rods is heated to a temperature that is at or slightly above its melting point, and droplets or fused particles of the material are accelerated in a gas stream. The droplets are directed against the surface of the substrate to be coated (the portion or component) where they adhere, solidify and form a continuous layer of lamellar structure. As a special feature of the discontinuous detonation spray process, the layer of individual overlapping, firmly joined spray marks is formed. Such methods are known in the art and described in detail in numerous publications.

While many attempts have been made to apply thermal, metal, ceramic or carbide based spray coatings directly to surfaces of fiber reinforced composites, usually only a low layer adhesion has been achieved, often the layers do not adhere to the fiber reinforced substrate or flake even after deposition of a small one layer thickness from. Typically, the component surface is roughened prior to application of the thermal spray coating to improve adhesion. The roughening is usually done by corundum blasting of the surface. However, corundum blasting or other forms of roughening of the surfaces to be coated may result in unacceptable erosion of the polymer matrix associated with exposure of the fibers. The latter, in turn, can permanently affect the layer properties.

These and other problems have become apparent, for example, in the application of in US-A-5,857,950 described method. Here, the surface of a carbon fiber roller is sandblasted and then applied as a heat shield zinc coating is applied. After re-sandblasting the now zinc-coated roller, an adhesive coating is applied, which may be a mixture of aluminum bronze and polyester. Subsequently, the adhesive coating is sandblasted and a ceramic sprayed coating applied and engraved. This procedure has proved unacceptable.

An alternative method is in EP 0 514 640 B1 shown. Here, a layer is first formed on the surface of a fiber reinforced composite material, which consists of a mixture of a synthetic resin and dispersed therein metallic particles. Upon curing of this layer, the surface is mechanically processed to expose the dispersed particles to chemically bond the particulate material to an outer layer material that is thermally sprayed onto the first layer. Although limited success has been achieved with this method, the mixture of synthetic resin and particulate material can not adhere well to the composite and tends to form globules of material on the surface, rendering it unsuitable for commercial production.

In the DE 100 37 212 A1 For example, a primer is applied to a plastic surface by means of a thermal spraying process, which may be in particular zinc, zinc alloys, aluminum alloys and / or exothermically reacting materials in the injection process, such as nickel-aluminum alloys. Subsequently, a functional coating likewise produced by means of a thermal spraying process is applied to the primer.

Furthermore, in the EP 1 129 787 B1 describes a coating process in which a fiber reinforced composite body is coated with a first layer containing only polymer, a second layer of a polymer / metal mixture and then a thermal spray coating. To one To achieve sufficient bond strength between the layers, suitable polymer materials must be selected for the first two coating layers.

Furthermore, in US 2002/187292 A1 describes a method for coating a component made of fiber-reinforced plastic, in which first a coating of hard rubber or thermoplastic with a metal or ceramic dispersion content of 5 vol% to 80 vol% is applied to the body of fiber-reinforced plastic, the applied coating is sanded until the dispersed metal or ceramic particles are to be seen on the surface, and then a functional layer of metal and / or ceramic is applied to the ground surface by means of thermal spraying.

It is an object of the present invention to provide coated fiber reinforced composite polymer materials in which the adhesion of the coating layers to the composite is even further improved. The present invention is concerned in particular with the task of improving the wear resistance of fiber-reinforced plastics by combining two or more thermally or kinetically sprayed layer systems.

This object is achieved in that on the surface of the fiber-reinforced plastic, first a thermally sprayed layer of a composite consisting of organic and metallic components is applied as an adhesive layer; on the adhesive layer, a thermally or kinetically sprayed layer with predominantly metallic portions is applied as an intermediate layer; and to the intermediate layer a thermally or kinetically sprayed functional metal cover layer, CERMET (metal-carbide composite), oxide ceramics or mixtures of the aforementioned materials, or mixtures thereof with plastic is applied. For the metal-plastic composite applied as an adhesive layer, a mixture of two or more different materials can be used during spraying. Instead of using two or more Tell streams during spraying, the wire or powdered spray material itself may consist of the composite material.

The object of the so-called adhesive layer is to create a better connection to the matrix of the fiber-reinforced base material by the plastic content, and at the same time to ensure a better wetting of free Ilegender fibers, which also has a favorable effect on the layer adhesion. The metallic components of the adhesive layer have the purpose of allowing a connection of the subsequently applied metallic intermediate layer.

This intermediate layer is essential for the final application of the functional topcoat. It serves as a stable substrate of the usually brittle, wear-resistant cover layer and at the same time brings about a moderate adaptation of the moduli of elasticity of the adhesive layer and cover layer. In addition, in the further coating of the component, for example by high-speed flame spraying or by detonation spraying, the metallic intermediate layer ensures uniform distribution and removal of the introduced heat. Without sufficient heat dissipation, local evaporation of the organic binder of the main body may occur, which in turn would result in detachment of the entire layer system.

The method proposed here makes it possible to produce coated components from fiber-reinforced composite materials which are also suitable for strong dynamic loads and components with a large layer area.

Preferred embodiments of the invention will become apparent from the dependent claims.

Preferably, the proportion of the organic matrix in the adhesion layer, e.g. Polyester, between 5 and 60%, more preferably between 20 and 50%, and most preferably between 30 and 40%.

The metallic portion of the adhesive layer, e.g. Aluminum, copper or nickel is preferably between 40 and 90%, more preferably between 60 and 80%.

The thickness of the adhesive layer is preferably 0.1 to 2 mm, more preferably 0.1 to 1 mm, and particularly preferably 0.2 to 0.4 mm.

In a particularly preferred embodiment, a 0.2 mm thick adhesive layer is applied by plasma spraying and consists of a metal-polyester composite. In another preferred embodiment, an approximately 0.1 to 1 mm thick metallic layer is sprayed onto the adhesive layer by a thermal spraying process.

In one embodiment, the thickness of the intermediate layer is 0.5 to 2 mm. The intermediate layer can be processed before the application of the cover layer, for example by grinding or turning to compensate for unevenness from previous operations.

It is favorable if the metallic intermediate layer is applied by means of a combustion-free method, such as arc spraying, plasma spraying or kinetic spraying In order to keep the heat input in the base material made of fiber-reinforced plastic as low as possible.

It is also favorable if a metallic material with the highest possible ductility is used for the intermediate layer.

In a further embodiment, the intermediate layer already consists of a metal-hard material composite, e.g. a kinetically sprayed aluminum-aluminum oxide composite layer to achieve an increase in strength.

In particular, if the coating of the fiber-reinforced material is intended to increase wear resistance, the functional top layer of the layer system is preferably an oxide ceramic (e.g., chromium oxide) or a CERMET (metal-carbide composite, e.g., tungsten carbide particles incorporated into a metallic cobalt matrix).

Claims (7)

1. Method for coating a member of fiber-reinforced composite material, characterized in that

   (a) at first a composite consisting of organic and metallic components is applied by means of thermal spraying as an adhesive layer to a surface of the member to be coated;

   (b) a layer predominantly comprising metallic components is applied by means of thermal or kinetic spraying as an intermediate layer to said adhesive layer; and

   (c) a functional covering layer consisting of metal, a metal-carbide composite, oxide ceramics or mixtures of said materials is applied to said intermediate layer by means of thermal or kinetic spraying.
2. Method as claimed in claim 1, characterized in that the organic component of the adhesive layer amounts to between 5 and 60 %, preferably between 20 and 50 %, and most preferably between 30 and 40 %.
3. Method as claimed in claim 1, characterized in that the metallic component of the adhesive layer amounts to between 40 and 90 %, and preferably between 60 and 80 %.
4. Method as claimed in any one of the preceding claims, characterized in that the thickness of the adhesive layer is between 0.1 and 2 mm, preferably between 0.1 and 1 mm, and more preferably between 0.2 and 0.4 mm.
5. Method as claimed in any one of the preceding claims, characterized in that the metallic component of the intermediate layer amounts to 60 % or more.
6. Method as claimed in any one of the preceding claims, characterized in that the thickness of the intermediate layer is between 0.1 and 2 mm, preferably between 0.2 and 1 mm, and most preferably between 0.3 and 0.6 mm.
7. Method as claimed in any one of the preceding claims, characterized in that the intermediate layer is machined before applying the covering layer.